Phytopathogenic fungi are the causal agents for many diseases that infect and destroy crops. In particular, the diseases sugar beet cercospora leaf spot, tomato early blight, apple scab and grape botrytis are especially devastating.
Sugar beet is susceptible to many foliar diseases caused by fungi. One of the most frequently encountered and destructive foliar diseases occurring on sugar beet is sugar beet cercospora leaf spot, caused by the fungus, Cercospora beticola. Sugar beet cercospora leaf spot is common to sugar beet throughout the world, and is particularly destructive in regions with wet, warm growing seasons, such as Western and Southern Europe and the Midwestern United States. During periods of high temperature and wetness, sugar beet cercospora leaf spot spreads rapidly. Ultimately, the disease kills sugar beet leaf tissue, resulting in reduced beet weight and sugar content.
Tomatoes are also susceptible to diseases caused by fungi. For example, the foliage, stem and fruit of the tomato plant may be attacked by a fungus, Alternaria solani, resulting in a disease called tomato early blight. Tomato early blight occurs wherever tomatoes are grown, but is most destructive in regions with wet, humid climates. Uncontrolled, tomato early blight causes the defoliation of the tomato plant, resulting in reduced fruit number and size.
The leaves and fruit of apple trees are susceptible to attack by a fungus, Venturia inaequalis, resulting in a disease called apple scab. The disease occurs wherever apples are grown, but is most common in the United States and Europe. Uncontrolled, apple scab results in deformed, low quality fruit.
Grapes and peppers are susceptible to attack caused by the fungus, Botrytis cinerea, causing grape botryitis and pepper botryitis. Grape botrytis, for example, is an especially destructive disease that destroys the cell walls of the fruit, resulting in bunch rot. Grape botrytis occurs wherever grapes are grown, but is most common in Europe.
In spite of the commercial fungicides available today, diseases caused by fungi still abound. Accordingly, there is ongoing research to create new and more effective fungicides for controlling or preventing fungal infestations.
Certain quinazolines are known to possess useful biological activity (see, e.g., The Journal of Science and Industrial Research, 15c, pages 1-7 (1956) and 13b, pages 451-452 (1954); Advances in Antimicrobial and Antineoplastic Chemotherapy, Progress in Research and Clinical Application, Proceedings of the International Congress of Chemotherapyl 7th, Prague, Aug. 23-28, 1971, Volume 1, ed. M. Hejzlar (Baltimore: University Park Press, 1972), pages 1081-1083; and Annals of Biochemistry and Experimental Mediciner 20, supplement, pages 493-504 (1960)). However, none of these documents refer to any fungicidal activity for such compounds.
It is therefore an object of the present invention to provide substituted quinazoline compounds which are highly effective for controlling or preventing phytopathogenic fungal infestations in agronomic crops, both growing and harvested.
It is also an object of the present invention to provide a method for the prevention, control or amelioration of a disease caused by a phytopathogenic fungus by contacting said fungus with a fungicidally effective amount of a substituted quinazoline compound.
These and other objects of the present invention will become more apparent from the detailed description thereof set forth below.